Excerpted from The Economics and Ethics of Private Property
I will first state this general theory of property as a set of rulings applicable to all goods, with the goal of helping to avoid all possible conflicts by means of uniform principles, and I will then demonstrate how this general theory is implied in the nonaggression principle. According to the nonaggression principle, a person can do with his body whatever he wants as long as he does not thereby aggress against another person’s body. Thus, that person could also make use of other scarce means, just as one makes use of one’s own body, provided these other things have not already been appropriated by someone else but are still in a natural unowned state.
As soon as scarce resources are visibly appropriated — as soon as somebody “mixes his labor” with them, as John Locke phrased it, and there are objective traces of this — then property (the right of exclusive control), can only be acquired by a contractual transfer of property titles from a previous to a later owner, and any attempt to unilaterally delimit this exclusive control of previous owners or any unsolicited transformation of the physical characteristics of the scarce means in question is, in strict analogy with aggressions against other people’s bodies, an unjustifiable action.
The compatibility of this principle with that of nonaggression can be demonstrated by means of an argumentum a contrario. First, it should be noted that if no one had the right to acquire and control anything except his own body (a rule that would pass the formal universalization test), then we would all cease to exist, and the problem of the justification of normative statements simply would not exist. The existence of this problem is only possible because we are alive, and our existence is due to the fact that we do not, indeed cannot, accept a norm outlawing property in other scarce goods next to and in addition to that of one’s physical body. Hence, the right to acquire such goods must be assumed to exist.
However, the position of property titles being acquired through declaration is incompatible with the above-justified nonaggression principle regarding bodies. For one thing, if one could indeed appropriate property by decree, this would imply that it would also be possible for one to simply declare another person’s body to be one’s own. Clearly enough, this would conflict with the ruling of the nonaggression principle, which makes a sharp distinction between one’s own body and the body of another person.Now, if this is so, and if one does not have the right to acquire such rights of exclusive control over unused, nature-given things through one’s own work (by doing something with things with which no one else has ever done anything before), and if other people have the right to disregard one’s ownership claim to things which they did not work on or put to some particular use before, then this is only possible if one can acquire property titles not through labor (i.e., by establishing some objective, intersubjectively controllable link between a particular person and a particular scarce resource), but simply by verbal declaration, by decree.
Furthermore, this distinction can only be made in such a clear-cut and unambiguous way because for bodies, as for anything else, the separation between “mine and yours” is not based on verbal declarations, but on action. The observation is based on some particular scarce resource that had in fact — for everyone to see and verify because objective indicators for this existed — been made an expression or materialization of one’s own will or, as the case may be, of somebody else’s will.
More importantly, to say that property could be acquired not through action but through a declaration would involve an obvious practical contradiction, because nobody could say and declare so unless his right of exclusive control over his body as his own instrument of saying anything was in fact already presupposed, in spite of what was actually said.
As I intimated earlier, this defense of private property is essentially also Murray Rothbard’s. In spite of his formal allegiance to the natural-rights tradition, Rothbard, in what I consider his most crucial argument in defense of a private-property ethic, not only chooses essentially the same starting point — argumentation — but also gives a justification by means of a priori reasoning almost identical to the one just developed. To prove the point I can do no better than simply quote:
Now, any person participating in any sort of discussion, including one on values, is, by virtue of so participating, alive and affirming life. For if he were really opposed to life, he would have no business continuing to be alive. Hence, the supposed opponent of life is really affirming it in the very process of discussion, and hence the preservation and furtherance of one’s life takes on the stature of an incontestable axiom.
In making this argument, one would not have to claim to have derived an “ought” from an “is.” In fact, one can readily subscribe to the almost generally accepted view that the gulf between “ought” and “is” is logically unbridgeable. Rather, classifying the rulings of the libertarian theory of property in this way is a purely cognitive matter. It no more follows from the classification of the libertarian ethic as “fair” or “just” that one ought to act according to it, than it follows from the concept of validity or truth that one should always strive for it.So far it has been demonstrated that the right of original appropriation through actions is compatible with and implied by the nonaggression principle as the logically necessary presupposition of argumentation. Indirectly, of course, it has also been demonstrated that any rule specifying different rights cannot be justified. Before entering a more detailed analysis, though, of why it is that any alternative ethic is indefensible, a discussion which should throw some additional light on the importance of some of the stipulations of the libertarian theory of property — a few remarks about what is and what is not implied by classifying these latter norms as justified is in order.
To say that it is just also does not preclude the possibility of people proposing or even enforcing rules that are incompatible with this principle. As a matter of fact, the situation with respect to norms is very similar to that in other disciplines of scientific inquiry. The fact, for instance, that certain empirical statements are justified or justifiable and others are not does not imply that everybody only defends objective, valid statements.
On the contrary, people can be wrong, even intentionally. But the distinction between objective and subjective, between true and false, does not lose any of its significance because of this. Instead, people who would do so would have to be classified as either uninformed or intentionally lying.
The case is similar with respect to norms. Of course there are people, lots of them, who do not propagate or enforce norms that can be classified as valid according to the meaning of justification I have given above. However, the distinction between justifiable and nonjustifiable norms does not dissolve because of this, just as that between objective and subjective statement does not crumble because of the existence of uninformed or lying people.
Rather, and accordingly, those people who would propagate and enforce such different, invalid norms would again have to be classified as uninformed or dishonest, insofar as one had made it clear to them that their alternative norm proposals or enforcements cannot and never will be justifiable in argumentation.
Why is it then that other nonlibertarian property theories fail to be justifiable? First, it should be noted, as will become clear shortly, that all of the practiced alternatives to libertarianism and most of the theoretically proposed nonlibertarian ethics would not even pass the first formal universalization test and would fail for this fact alone!There would be even more justification for doing so in the moral case than in the empirical one, since the validity of the nonaggression principle and that of the principle of original appropriation through action as its logically necessary corollary must be considered to be even more basic than any kind of valid or true statements. For what is valid or true has to be defined as that upon which everyone — acting according to this principle — can possibly agree. As I have just shown, at least the implicit acceptance of these rules is the necessary prerequisite to being able to be alive and argue at all.
All these versions contain norms within their framework of legal rules that have the form, “some people do, and some people do not.” However, such rules that specify different rights or obligations for different classes of people have no chance of being accepted as fair by every potential participant in an argument for simply formal reasons.
Unless the distinction made between different classes of people happens to be such that it is acceptable to both sides as grounded in the nature of things, such rules would not be acceptable because they would imply that one group is awarded legal privileges at the expense of complementary discriminations against another group. Some people, either those who are allowed to do something or those who are not, would not be able to agree that these were fair rules.
Since most alternative ethical proposals, as practiced or preached, have to rely on the enforcement of rules such as “some people have the obligation to pay taxes, and others have the right to consume them,” or “some people know what is good for you and are allowed to help you get these alleged blessings even if you do not want them, but you are not allowed to know what is good for them and help them accordingly,” or “some people have the right to determine who has too much of something and who too little, and others have the obligation to accept that,” or even more plainly, “the computer industry must pay to subsidize the farmers, the employed for the unemployed, the ones without kids for those with kids,” or vice versa. They all can be discarded as serious contenders to the claim of being a valid theory of norms qua property norm, because they all indicate by their very formulation that they are not universalizable.
There are two related specifications in the libertarian property theory with at least one of which any alternative theory comes into conflict. According to the libertarian ethic, the first such specification is that aggression is defined as an invasion of the physical integrity of other people’s property. There are popular attempts to define it as an invasion of the value or psychic integrity of other people’s property. Conservatism, for instance, aims at preserving a given distribution of wealth and values and attempts to bring those forces that could change the status quo under control by means of price controls, regulations, and behavioral controls. Clearly, in order to do so, property rights to the value of things must be assumed to be justifiable, and an invasion of values, mutatis mutandis, would have to be classified as unjustifiable aggression.What is wrong with a nonlibertarian ethic if this is resolved and there is indeed a theory formulated that contains exclusively universalizable norms of the type “nobody is allowed to” or “everybody can”? Even then the validity of such proposals could never hope to be proven — not because of formal reasons but because of their material specifications. Indeed, while the alternatives that can be refuted easily as regards their claim to moral validity on simple formal grounds can at least be practiced, the application of those more sophisticated versions that would pass the universalization test would prove for material reasons to be fatal: even if one tried to, they simply could never be implemented.
Not only does conservatism use this idea of property and aggression; redistributive socialism does too. Property rights to values must be assumed to be legitimate when redistributive socialism allows me, for instance, to demand compensation from people whose chances or opportunities negatively affect mine. The same is true when compensation for committing psychological, or “structural violence” is requested. In order to be able to ask for such compensation, what one must have done, namely affect my opportunities, my psychic integrity, or my feeling of what is owed to me, would have to be classified as an aggressive act.
Why is this idea of protecting the value of property unjustifiable? First, while every person, at least in principle, can have full control over whether or not his actions cause the physical characteristics of something to change and hence can also have full control over whether or not those actions are justifiable, control over whether or not one’s actions affect the value of somebody else’s property does not rest with the acting person but rather with other people and their subjective evaluations. Thus, no one could determine ex ante if his actions would be qualified as justifiable or unjustifiable.
One would first have to interrogate the whole population to make sure that one’s planned actions would not change another person’s evaluations regarding his own property. Even then, nobody could act until universal agreement was reached on who is supposed to do what with what, and at which point in time.
However, in order to argue that there is a way out of such conflicts it must be presupposed that actions must be allowed prior to any actual agreement or disagreement because if they were not, one could not even argue so. Yet if one can do this (and, insofar as it exists as an argued intellectual position, the position under scrutiny must assume that one can), then this is only possible because of the existence ofobjective borders of property — borders which anyone can recognize as such on his own without having to agree first with anyone else with respect to his system of values and evaluations.Clearly, because of all the practical problems involved, everyone would be long dead and nobody could argue any longer, well before agreement could be reached. Even more decisively, this position regarding property and aggression could not even be effectively argued because arguing in favor of any norm implies that there is conflict over the use of some scarce resources; otherwise there would simply be no need for discussion.
Such a value-protecting ethic, too, in spite of what it says, must in fact presuppose the existence of objective property borders rather than of borders determined by subjective evaluations, if only in order to have any surviving persons who can make its moral proposals.
The idea of protecting value instead of physical integrity also fails for a second related reason. Evidently, one’s value, for example on the labor or marriage market, can be and indeed is affected by other people’s physical integrity or degree of physical integrity. Thus, if one wanted property values to be protected, one would have to allow physical aggression against people.
However, it is only because of the very fact that a person’s borders — that is the borders of a person’s property in his own body as his domain of exclusive control, which another person is not allowed to cross unless he wishes to become an aggressor — are physical borders (intersubjectively ascertainable, and not just subjectively fancied borders) that everyone can agree on anything independently (and agreement means agreement among independent decision-making units!).
Only because the protected borders of property are objective (i.e., fixed and recognizable as fixed prior to any conventional agreement), can there be argumentation and possibly agreement of and between independent decision-making units. Nobody could argue in favor of a property system defining borders of property in subjective, evaluative terms because simply to be able to say so presupposes that, contrary to what theory says, one must in fact be a physically independent unit saying it.
It is with this additional specification as well that alternative, nonlibertarian ethics come into conflict. Instead of recognizing the vital importance of the prior-later distinction in deciding between conflicting property claims, they propose norms which in effect state that priority is irrelevant for making such a decision and that late-comers have as much of a right to ownership as first-comers.The situation is no less dire for alternative ethical proposals when one turns to the second essential specification of the rulings of the libertarian theory of property. The basic norms of libertarianism are characterized not only by the fact that property and aggression are defined in physical terms; it is of no less importance that property is defined as private, individualized property, and that the meaning of original appropriation, which evidently implies making a distinction between prior and later, has been specified.
Clearly, this idea is involved when redistributive socialism makes the natural owners of wealth and/or their heirs pay a tax so that the unfortunate late-comers can participate in its consumption. It is also involved when the owner of a natural resource is forced to reduce (or increase) its present exploitation in the interest of posterity. Both times it only makes sense to do what one does when it is assumed that the person accumulating wealth first, or using the natural resource first, has thereby committed an aggression against some late-comers. If they had done nothing wrong, then the late-comers should have no such claim against them.
What is wrong with this idea of dropping the prior-later distinction as morally irrelevant? First, if the late-comers (those who did not do something with some scarce goods), indeed had as much of a right to them as the first-comers (those who did do something with the scarce goods), then nobody would ever be allowed to do anything with anything, as one would have to have all of the late-comers’ consent prior to doing what one wanted to do.
Indeed, as posterity would include one’s children’s children — people who come so late that one could not possibly ask them — to advocate a legal system that does not make use of the prior-later distinction as part of its underlying property theory is simply absurd, because it implies advocating death but must presuppose life to advocate anything.
Rather, insofar as a person finds himself alone, he must be able to act, to use, to produce, and to consume goods straightaway, prior to any agreement with people who are simply not around (and perhaps never will be). Insofar as a person finds himself in the company of others and there is conflict over how to use a given scarce resource, he must be able to resolve the problem at a definite point in time with a definite number of people instead of having to wait unspecified periods of time for unspecified numbers of people.Neither we, nor our forefathers, nor our progeny could, do, or will survive and say or argue anything if one followed this rule. In order for any person — past, present or future — to argue anything it must be possible to survive now. Nobody can wait and suspend acting until everyone of an indeterminate class of late-comers happens to come around and agree to what one wants to do.
Simply in order to survive, then, which is a prerequisite to arguing in favor or against anything, property rights cannot be conceived of as being timeless and nonspecific regarding the number of people concerned. Rather, they must be thought of as originating through acting at definite points in time for definite acting individuals.
Furthermore, the idea of abandoning the prior-later distinction would simply be incompatible with the nonaggression principle as the practical foundation of argumentation. To argue and possibly agree with someone (if only on the fact that there is disagreement) means to recognize the prior right of exclusive control over one’s own body. Otherwise, it would be impossible for anybody to say anything at a definite point in time and for someone else to be able to reply, for neither the first nor the second speaker would be a physically independent decision-making unit anymore at any time.
Eliminating the prior-later distinction, then, is tantamount to eliminating the possibility of arguing and reaching agreement.
However, as one cannot argue that there is no possibility for discussion without the prior control of every person over his own body being recognized and accepted as fair, a late-comer ethic that does not make this distinction could never be agreed upon by anyone. Simply saying that it could be would imply a contradiction, for one’s being able to say so would presuppose one’s existence for an independent decision-making unit at a definite point in time.
Hence, one is forced to conclude that the libertarian ethic not only can be justified and justified by means of a priori reasoning, but that no alternative ethic can be defended argumentatively.
 John Locke, Two Treatises on Government, ed. Peter Laslett (Cambridge: Cambridge University Press, 1970), esp. vols. II, V.Notes
 This is the position taken by Jean-Jacques Rousseau, when he asks us to resist attempts to privately appropriate nature-given resources by, for example, fencing them in. He says in his famous dictum; “Beware of listening to this impostor, you are undone if you once forget that the fruits of the earth belong to us all, and the earth itself to nobody” (“Discourse upon the Origin and Foundation of Inequality Among Mankind,” in Jean-Jacques Rousseau, The Social Contract and Discourses, ed. G.D.H. Cole [New York: 1950], p. 235). However, to argue so is only possible if it is assumed that property claims can be justified by decree. How else could “all” (even those who never did anything with the resources in question) or “nobody” (not even those who made use of it) own something unless property claims were founded by mere decree?
 Rothbard, The Ethics of Liberty, p. 32; on the method of a priori reasoning employed in the above argument see also, idem, Individualism and the Philosophy of the Social Sciences (San Francisco: Cato Institute, 1979); Hans-Hermann Hoppe, Kritik der kausalwissenschaftlichen sozialforschung. Untersuchungen zur Grundlegung von Soziologie und Ökonomie (Opladen: Westdeutscher Verlag 1983); idem, “Is Research Based on Causal Scientific Principles Possible in the Social Sciences? Ratio (1983); supra chap. 7; idem, A Theory of Socialism and Capitalism, chap. 6.
 See Rothbard, The Ethics of Liberty, p. 45.
 On the importance of the definition of aggression as physical aggression see also Rothbard, ibid., chaps. 8—9; idem, “Law, Property Rights and Air Pollution,” Cato Journal (Spring, 1982).
 On the idea of structural violence as distinct from physical violence see Dieter Senghass, ed., Imperialismus und strukturelle Gewalt (Frankfurt/M.: Suhrkamp, 1972). The idea of defining aggression as an invasion of propertyvalues also underlies both the theories of justice of John Rawls and Robert Nozick, however different these two authors may have appeared to be to many commentators. For how could Rawls think of his so-called difference-principle (“Social and economic inequalities are to be arranged so that they are reasonably expected to be to everyone’s — including the least advantaged ones — advantage or benefit,” John Rawls, A Theory of Justice[Cambridge, Mass.: Harvard University Press 1971], pp. 60—83, 75ff.), as justified unless he believes that simply by increasing his relative wealth a more fortunate person commits an aggression, and a less fortunate one then has a valid claim against the more fortunate person only because the former’s relative position in terms of value has deteriorated?! And how could Robert Nozick claim it to be justified for a “dominant protection agency” to outlaw competitors, regardless of what their actions would have been like? (Robert Nozick, Anarchy, State, and Utopia [New York: Basic Books, 1974], pp. 55f.) Or how could he believe it to be morally correct to outlaw so-called nonproductive exchanges, i.e., exchanges where one party would be better off if the other one did not exist at all or at least had nothing to do with it (as, for instance, in the case of a blackmailee and a blackmailer), regardless of whether or not such an exchange involved physical invasion of any kind (ibid., pp. 83—86) unless he thought that the right to have the integrity of one’s property values (rather than its physical integrity) preserved existed? For a devastating critique of Nozick’s theory in particular see Rothbard, The Ethics of Liberty, chap. 29; on the fallacious use of the indifference curve analysis, employed both by Rawls and Nozick, idem, Toward a Reconstruction of Utility and Welfare Economics (New York: Center for Libertarian Studies, Occasional Paper Series, No. 3, 1977)
 See also Rothbard, The Ethics of Liberty, p. 46.
 For an awkward philosophical attempt to justify a late-comer ethic see James P. Sterba, The Demands of Justice (Notre Dame, Ind.: Notre Dame University Press, 1980), esp. pp. 58ff., 137ff.; on the absurdity of such an ethic see Rothbard, Man, Economy, and State, p. 427.
 It should be noted here that only if property rights are conceptualized as private-property rights originating in time does it then become possible to make contracts. Clearly enough, contracts are agreements between enumerable physically independent units which are based on the mutual recognition of each contractor’s private ownership claims to things acquired prior in time to the agreement and which then concern the transfer of property titles to definite things from a definite prior to a definite later owner. No such thing as contracts could conceivably exist in the framework of a late-comer ethic!
Reprinted from Mises.org.